Utility system design

SINGH, J., HADA, K., JAERI/KFA Cooperation on Nuclear Heat Utilization System Design and Safety, Internal Report KFA-ISR-EB-16/94, Research Center Julich (1994). 

The energy cost of the process can be set without having to design the heat exchanger network and utility system. These energy targets cam be calculated directly from the material and energy balance. Thus... 

DP Speed Factor. Pumping-speed efficiency depends on trap, valve, and system design. For gases having velocities close to the molecular velocity of the DP top jet, system-area utilization factors of 0.24 are the maximum that can be anticipated eg, less than one quarter of the molecules entering the system can be pumped away where the entrance area is the same as the cross-sectional area above the top jet (see Fig. 4). The system speed factor can be quoted together with the rate of contamination from the pump set. Utilization factors of <0.1 for N2 are common. 

It is important for crosstied systems that a sufficient condensate network is provided for balancing the mix of condensate return and makeup treated water as required. The author has seen a system designed with process area and utility area fired boilers of the same pressure. Periodically, the utility area was required to supply makeup steam to balance a shortage in the process area, but no provisions were made to return equivalent condensate from the process to the utility area. The earlier such a mistake is caught, the better. 

System designers often think dampers bloek airflow and are suitable to prevent baek drafts in idle towers. This is not the ease. Airfoil dampers simply hamper fan housing efficiency- they do not block airflow. Air Inlet Screens are always part of blow through, counterflow towers to protect people from rotating equipment. Some designs can be a hazard when accessible from the underside and require the specifier to call out additional screening. They can be a worthwhile accessory when there are nearby trees even when not required for safety reasons. Air inlet screens should be eliminated on towers utilizing inlet ductwork. Inlet ductwork may also make it necessary to block extraneous air entry such as from the underside when towers are elevated. 

The electrical distribution system design and equipment selection must consider requirements of the utility company for protection and metering. Available short circuit currents from the utility distribution network to the primary of the facility s main transfoiTner must be considered in selecting circuit protection devices for the facility distribution system. 

For final design horsepower and equipment selection, the usual practice is to submit the refrigeration load and utility conditions/requirements to a reputable refrigerant system designer/manufacturer and obtain a warranted system with equipment and instrumentation design and specifications including the important materials of construction. Always request detailed operating instructions/controls and utility quantity requirements. 

Develop device or system designs utilizing the descriptive governing relationships between the dimensionless terms (and subsequently between the variables) that are similar to those of the tested physical model, but are the dimensional scale of the desired device or system. 

Polymers conjugated with 1-adamantyl moieties as lipophilic pendent groups can be utilized to design nanoparticulate dmg delivery systems. Polymer (1) in Fig. 26, which is synthesized by homopolymerization of ethyladamantyl malolactonate, can be employed as highly hydrophobic blocks to construct... 

Most processes operate in the context of an existing site in which a number of processes are linked to the same utility system. The utility systems of most sites have evolved over a period of many years without fundamental questions being addressed as to the design and operation of the utility system. The picture is complicated by individual production processes on a site belonging to different business areas, each assessing investment proposals independently from one another and each planning for the future in terms of their own business. Yet, the efficiency of the site infrastructure and the required investment is of strategic importance and must be considered across the site as a whole, even if this crosses the boundaries of different business areas. 

A grassroot utility system may need to be designed. However, this is rare, and most situations would involve modification of an existing system. 

The outer layers of the onion (the utility system) produce utility waste. The utility waste is products of fuel combustion, waste from the production of boiler feedwater for steam generation, and so on. However, the design of the utility system is closely tied together with the design of the heat exchanger network. Hence, in practice, the three outer layers should be considered as being the source of utility waste. 

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